Loads and loads of people sound great with mixed speakers, broken equipment, all sorts of 'incorrect' rigs in every way. Loads of people (more I'd argue) sound awful. Every real life situation decreases the effectiveness of every rig, I'd prefer having a rig that has better dispersion etc to help me fight my battles rather than also having to fight my amp.
Being educated can only, only help. That way if choose to disregard the correct way of doing things, you know exactly what you're doing and why it sounds good enough to justify doing it incorrectly.